A hallmark of early phonological development is the presence of both inter- and intra-word variability, phenomena that traditional linguistic theories often have difficulty accounting for. Recent evidence suggests that observed variability may be systematically influenced by lexical development. The overall objective of this project is to investigate lexical-phonological interactions in development. Specifically, the lexical characteristics of word frequency (WF), neighborhood density (ND), and age-of-acquisition (AOA) will be studied in relation to the accuracy and variability of single word productions by typically developing toddlers. The project will consist of a longitudinal transcription-based investigation (19-29 months) of production accuracy and variability in relation to the variables of WF, ND, and ADA. The theoretical framework adopted is that of Usage-based phonology which emphasizes the role of language use in the construction of a phonological system. The results of this study will enhance our understanding of lexicalphonological interactions in typical development, which may in turn help us to better understand the nature of phonological deficits and will inform our decisions regarding appropriate treatment methods and targets.